package main

import "fmt"

func main() {
	a := make(map[int]int, 3)
	a[1] = 1
	a[2] = 2
	a[3] = 3
	a[4] = 4
	fmt.Printf("%+v \n", a)
	b := new(int)
	fmt.Println("------------")
	fmt.Printf("%+v \n", *b)

	type Demo struct {
		Name string
	}
	demo := new(Demo)
	fmt.Println("------------")
	fmt.Printf("%+v \n", demo)
	demo.Name = "zhangsan"
	fmt.Println("------------")
	fmt.Printf("%+v \n", demo)
	var d *Demo

	fmt.Println("------------")
	fmt.Printf("%+v \n", d)
}
